There is a short recent discussion of them at [
www.mysteryshopforum.com]
In my market there are not many shops offered, but I am delighted to do them. I have done a few for a fee, more for reimbursement only, but have always been pleased. Pay/reimbursement is generally towards the end of the month following shop review and acceptance. Feedback is given on their website and appears within 2-3 days of shop submission. I have found the feedback useful.